The hazards of asbestos for brake mechanics

Our plain-English summary of The hazards of asbestos for brake mechanics, by B. Castleman, L.A. Camarota, A.J. Fritsch, et al (Public Health Reports, 1975).

The study

• Authors: B. Castleman, L.A. Camarota, A.J. Fritsch, S. Mazzocchi, R.G. Crawley
• Journal: Public Health Reports
• Published: 1975;90(3):254-6
• Cited by: 14 articles, as counted by NIH iCite
• Read it: PubMed · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 002697).

Summary of the article

The authors described two programs that warned brake repair establishments about the hazard of asbestos dust and assessed whether the warnings changed work practices. Brake friction materials were reported to contain an average of 50 percent chrysotile, and the usual method of removing brake dust was blowing it out with a compressed air hose. In December 1972 the Baltimore County Department of Health mailed a one-page circular to about 130 brake repair establishments. It warned that brake dust could cause serious diseases, including cancer, and advised vacuuming, better ventilation and face masks. Four months later, student volunteers visited 100 establishments. In Washington, D.C., starting in August 1973, an occupational health nurse handed a more readable leaflet directly to mechanics at 186 establishments and later interviewed managers at 120. Initially, 65 percent (65 of 100) of Baltimore shops and 91 percent (110 of 120) of Washington shops were blowing out brakes. At follow-up, 11 of the 65 Baltimore shops used vacuum or wet brushing, and 4 others had added ventilation or masks. In Washington, 2 shops changed to wet brushing, 4 provided masks and 2 changed brake shoes in all repairs. Improvement was 23 percent in Baltimore County and 7 percent in Washington. The authors suggested that failing to involve management may explain the poorer Washington result. They concluded that voluntary warnings had limited effect and that blowing out brakes would remain common as long as regulations permitted it.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

Two programs warned brake repair shops about asbestos in brake dust. In Baltimore County, a circular was mailed to about 130 establishments in December 1972, and students visited 100 of them four months later. In Washington, D.C., from August 1973, a nurse handed leaflets to mechanics and followed up 120 of 186 establishments. Blowing dust out with compressed air was the method at 65 of 100 Baltimore shops and 110 of 120 Washington shops. Most managers and workers interviewed had never heard of the hazard. The authors' improvement index after one warning was 23 percent in Baltimore County and 7 percent in Washington. In Baltimore, 11 of 65 blow-out shops moved to vacuum or wet brushing, and 4 kept blowing out but added ventilation or masks. In Washington, 2 changed to wet brushing, 4 provided masks and 2 decided to change brake shoes in all repairs. Local vocational schools were teaching the blow-out method. The authors attributed the difference between the cities mainly to study methods, possibly the failure to involve management in Washington. They concluded that voluntary warnings had limited effect and that blowing out brakes would continue while regulations allowed it.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Public health intervention with follow-up survey: warning circulars or leaflets were given to brake repair establishments, and the shops were later contacted again to see whether brake-cleaning methods had changed
• Who was studied: Brake repair establishments in Baltimore County (about 130 mailed in December 1972, 100 visited 4 months later) and in Washington, D.C. (186 contacted starting August 1973, 120 followed up), including new car and truck dealerships, certified motor vehicle inspection stations, and shops advertising brake repair
• Exposure: Asbestos-containing brake dust released when mechanics cleaned brakes, mainly by blowing it out with a compressed air hose. Citing earlier work, the article states that brake friction materials averaged 50 percent chrysotile by weight. This study recorded cleaning methods, not dust levels.
• Main results:
  • At the time of the warning, 65 of 100 Baltimore establishments contacted were blowing out brakes with compressed air
  • In Washington, 91 percent (110 of 120) of establishments were blowing out brakes (printed as "1 10" in the scanned text; 110 of 120 matches the stated 91 percent)
  • Most managers and workers interviewed had never heard about the hazard of brake dust
  • In Baltimore, of the 65 shops initially blowing out brakes, 11 were using vacuum or wet brushing at follow-up, and 4 others still blew out brakes but had improved ventilation or provided dust masks, or both
  • In Washington, 2 establishments changed to wet brushing, none were vacuuming, 4 provided face masks, and 2 decided to change brake shoes in all brake repairs
  • The authors' index of improvement after a single warning was 23 percent in Baltimore County and 7 percent in Washington. The shops counted include some that still blew out brakes but added ventilation or masks.
  • School officials in Baltimore and Washington reported that public vocational schools were teaching the blow-out method to brake repair trainees
• The authors' conclusion: The authors concluded that the limited success of both programs showed the limited effect of voluntary compliance with health warnings, and that blowing out brakes would remain common as long as health regulations permitted it. They suggested that failing to involve management may have been the main reason Washington had poorer results.
• Limitations the authors state:
  • The authors noted that the two cities' results are hard to compare directly. They attributed the difference mainly to differences in how the two studies were carried out rather than to differences between the shops studied.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Auto mechanics and brake work.

Medical terms in this study, explained in our Lexicon: Chrysotile, Brake Lining.

Related studies

• Environmental and occupational health hazards associated with the presence of asbestos in brake linings and pads (1900 to present): a "state-of-the-art" review — D.J. Paustenbach, B.L. Finley, et al. (2004)
• Cumulative asbestos exposure for US automobile mechanics involved in brake repair (circa 1950s-2000) — B.L. Finley, R.O. Richter, et al. (2007)
• An evaluation of short-term exposures of brake mechanics to asbestos during automotive and truck brake cleaning and machining activities — R.O. Richter, B.L. Finley, et al. (2009)
• Pleural mesothelioma in a brake mechanic — M. Huncharek, J. Muscat, et al. (1989)
• Brake mechanics, asbestos, and disease risk — M. Huncharek (1990)
• Warning auto mechanics about asbestos hazards — J. LaDou (2004)

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